The interplay between frailty status and persistent critical illness on the outcomes of patients with critical COVID-19: A population-based retrospective cohort study.

Abstract

Objectives: Persistent critical illness (PerCI) occurs when the patient's prolonged intensive care unit (ICU) stay results in complications that become the primary drivers of their condition, rather than the initial reason for their admission. Patients with frailty have a higher risk of developing and dying from PerCI. We aimed to investigate the interplay of frailty and PerCI in critically ill patients with COVID-19.

Method: We conducted a retrospective multicentre cohort study including 103 Australian and New Zealand ICUs over the period of January 2020 to December 2021. We included all adult patients with COVID-19 and documented the Clinical Frailty Scale (frail ≥ 5). PerCI is defined as an ICU length of stay of ≥10 days. We aimed to investigate the hospital mortality with and without PerCI across varying degrees of frailty and examined the potential interaction effect between frailty status and PerCI.

Results: The prevalence of PerCI was similar between patients with and without frailty (25.4% vs. 27.9%; p = 0.44). Hospital mortality was higher in patients with PerCI than in those without (28.8% vs. 9.3%; p < 0.001). Mortality in patients with PerCI also increased with increasing frailty (p < 0.001). Frailty independently predicted hospital mortality. When adjusted for Australia and New Zealand risk of death mortality prediction model and sex, the impact of frailty was no different in patients with and without PerCI (odds ratio = 1.30 [95% confidence interval: 1.14-1.49] vs. (odds ratio = 1.46 [95% confidence interval: 1.29-1.64]). Furthermore, increasing frailty did not influence mortality in patients with PerCI more (or less) than in those without PerCI (p_interaction = 0.82).

Conclusions: The presence of frailty independently predicted hospital mortality in patients with PerCI with COVID-19, but the impact of frailty on mortality was no different in those who developed PerCI from those without PerCI.